This invention relates, in general, to mold manufacturing and, more particularly, to generation of patterns and transferring of the patterns to molding surfaces of the mold.
At present, materials used for making transfer molds and injection molds typically are very hard durable metals, such as steel, high carbon steel, and the like. Patterning or shaping of these materials into various geometric patterns that ultimately defines geometric forms of the molded objects is a very difficult task.
Generally, shaping or patterning of molds is achieved by several machine technologies, such as milling, grinding, and wire electronic discharge machining (EDM) that cut away or remove material from the mold, thus slowly shaping the mold to a desired form. However, these machine technologies do not provide sufficient precision, accuracy, or resolution required for patterning of molds used for optical applications. At best, these technologies provide precision, accuracy, and resolution of only .+-.2 microns, thus not enabling the patterning of molding beyond these limits.
Moreover, these machine technologies generally are only capable of straight line structures, thus not allowing a variety of geometric forms or patterns to be transferred into molding surfaces of the mold, thus severely limiting the patterning capability of making molds. This limitation of patterning capability in turn limits objects that are capable of being molded. Further, profiles of the patterns generated by these machine technologies are dictated by the shape and size of a tool used in each specific technology for generating the pattern. However, a greater degree of shape specificity is required in today's and tomorrow's molding environment.
It can be readily seen that conventional removal or cutting away methods of patterning molds have severe limitations. Also, it is evident that conventional processing used for making these patterns are not capable of being able to provide geometric variations which further limit the ability of creating molded objects. Additionally, as profiles of molded objects become increasingly important, methods used at present are not capable of providing profile shapes that are required for molds, hence the molded objects. Therefore, a method for patterning molds that provides greater precision, accuracy, feature size, a variety of geometric patterns, and enable profile determination to be refined would be highly desirable.